[R] Concave hull

[Kjetil Halvorsen]

There is a package on CRAN implementing such an idea:
alphahull, phull is other package,

kjetil

On Thu, Nov 26, 2009 at 6:11 PM, baptiste auguie
<baptiste.auguie at googlemail.com> wrote:
> 2009/11/26 Ted Harding <Ted.Harding at manchester.ac.uk>:
>> Raising a rather general question here.
>>
>> This is a tantalising discussion, but the notion of "concave hull"
>> strikes me as extremely ill-defined!
>>
>> I'd like to see statement of what it is (generically) supposed to be.
>
> I'm curious too, but I can imagine the following definition,
>
> Consider a sphere (n-dimensional maybe) that we let come in contact
> with the scatter of points from outside. The set of points that the
> sphere can attain may define unambiguously (I think) a concave hull,
> for a specified sphere radius. The convex hull is obtained in the
> limit of infinite radius (plane).
>
> It's probably not exactly this, but I guess that's the rough idea.
>
> Just a thought,
>
> baptiste
>
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